Book Image

C++20 STL Cookbook

By : Bill Weinman
Book Image

C++20 STL Cookbook

By: Bill Weinman

Overview of this book

Fast, efficient, and flexible, the C++ programming language has come a long way and is used in every area of the industry to solve many problems. The latest version C++20 will see programmers change the way they code as it brings a whole array of features enabling the quick deployment of applications. This book will get you up and running with using the STL in the best way possible. Beginning with new language features in C++20, this book will help you understand the language's mechanics and library features and offer insights into how they work. Unlike other books, the C++20 STL Cookbook takes an implementation-specific, problem-solution approach that will help you overcome hurdles quickly. You'll learn core STL concepts, such as containers, algorithms, utility classes, lambda expressions, iterators, and more, while working on real-world recipes. This book is a reference guide for using the C++ STL with its latest capabilities and exploring the cutting-edge features in functional programming and lambda expressions. By the end of the book C++20 book, you'll be able to leverage the latest C++ features and save time and effort while solving tasks elegantly using the STL.
Table of Contents (13 chapters)

Create a disk usage counter

This is a simple utility that totals the size of every file in a directory and its sub-directories. It runs on both POSIX/Unix and Windows file systems.

How to do it…

This recipe is a utility to report the size of every file in a directory and its sub-directories, along with a total. We'll re-use some of the functions we've used elsewhere in this chapter:

  • We start with a few convenience aliases:
    namespace fs = std::filesystem;
    using dit = fs::directory_iterator;
    using de = fs::directory_entry;
  • We also use our format specialization for fs::path objects:
    template<>
    struct std::formatter<fs::path>: std::formatter<std::string> {
        template<typename FormatContext>
        auto format(const fs::path& p, FormatContext& ctx) {
            return format_to(ctx.out(), "{}", p.string());
        }
    };
  • ...